arch/arm/include/asm/macro.h

/*
 * include/asm-arm/macro.h
 *
 * Copyright (C) 2009 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
 *
 * See file CREDITS for list of people who contributed to this
 * project.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307 USA
 */

#ifndef __ASM_ARM_MACRO_H__
#define __ASM_ARM_MACRO_H__
#ifdef __ASSEMBLY__

/*
 * These macros provide a convenient way to write 8, 16 and 32 bit data
 * to any address.
 * Registers r4 and r5 are used, any data in these registers are
 * overwritten by the macros.
 * The macros are valid for any ARM architecture, they do not implement
 * any memory barriers so caution is recommended when using these when the
 * caches are enabled or on a multi-core system.
 */

.macro	write32, addr, data
	ldr	r4, =\addr
	ldr	r5, =\data
	str	r5, [r4]
.endm

.macro	write16, addr, data
	ldr	r4, =\addr
	ldrh	r5, =\data
	strh	r5, [r4]
.endm

.macro	write8, addr, data
	ldr	r4, =\addr
	ldrb	r5, =\data
	strb	r5, [r4]
.endm

/*
 * This macro generates a loop that can be used for delays in the code.
 * Register r4 is used, any data in this register is overwritten by the
 * macro.
 * The macro is valid for any ARM architeture. The actual time spent in the
 * loop will vary from CPU to CPU though.
 */

.macro	wait_timer, time
	ldr	r4, =\time
1:
	nop
	subs	r4, r4, #1
	bcs	1b
.endm

#endif /* __ASSEMBLY__ */
#endif /* __ASM_ARM_MACRO_H__ */